There are two major aspects of this work which involves the interaction of copper salts with organosulfur compounds. The first is concerned with the generation of copper-carbene complexes by the reactions of sulfur ylides with copper salts and the capture of these complexes by olefins in intramolecular as well as intermolecuar fashions; it is hoped that in this way one can perform biogenetic-type syntheses of a number of naturally occurring cyclopropanes. The other aspect involves the development of a number of new synthetic tools derived fron a key reaction discovered during this biogenetic study, the abstraction by a dissolved copper (I) ion of a thiophenoxide ion from a thioketal or a thiocetal to produce a sulfur-stabilized carbonium ion which can lose a proton to form a vinyl sulfide, rearrange, or ring close.